The on-page script here is trivial and uses a built-in method, but the external script in this page is nontrivial (defines a function)

The external script is blocked, the inline script is executed.

Code on this page:

<script src="external.js"></script>

<script>
alert('internal script');
</script>

Code in the external file, external.js

var myAlert = function () {
    alert("external script");
}

myAlert();